UNITED STATES: In a significant stride towards resolving the pressing issue of nuclear waste management, a team of researchers from the University of Houston has developed a groundbreaking solution using molecular crystals.
These crystals possess the extraordinary capability to effectively capture iodine, a common radioactive fission product. The potential applications of these crystals could revolutionize the maintenance of nuclear reactors and waste containers while offering the added advantage of recyclability.
With global consciousness escalating regarding the environmental and geopolitical impacts of fossil fuel consumption, nuclear power has emerged once again as a subject of considerable attention. Its capacity to generate electricity on a large scale without significant greenhouse gas emissions presents an alluring prospect for a clean and sustainable energy source. This opens the pathway for a transition towards a net-zero emissions future.
Yet, the production of nuclear energy results in the generation of radioactive waste, necessitating the safe handling and disposal of this hazardous material. Addressing this concern is pivotal to gaining public trust and full acceptance of nuclear power as a game-changing energy solution.
The molecular crystals developed by the researchers at the University of Houston are based on cyclotetrabenzyl hydrazones, a discovery made by the team in 2015. These crystals exhibit the remarkable ability to capture iodine from both aqueous and organic solutions, as well as at the interface between these two phases.
The significance of trapping iodine at interfaces lies in its potential to prevent the radioactive substance from reaching and damaging the specialized paint coatings used in nuclear reactors and waste containers. These crystals boast an astounding iodine uptake capacity that rivals leading materials such as porous metal-organic structures (MOFs) and covalent organic frameworks (COFs), previously considered the gold standard for iodine capture.
Alexandra Robles, the primary author of the study and a former doctoral scholar, worked in Professor Ognjen Miljanic’s lab, where her interest in addressing nuclear waste issues led her to investigate crystals for iodine capture. The property of these crystals to halt the transfer of iodine between organic and aqueous layers offers a significant advantage, ensuring the preservation of reactor coatings and improving containment.
Moreover, the captured iodine can be moved from one location to another, allowing the material to be trapped in difficult-to-manage areas and then released in more manageable locations. A crucial benefit of this catch-and-release technology is that the crystals can be reused, reducing waste generation and mitigating financial losses associated with contamination.
The molecular crystals, appearing like a powder due to their small size, are composed of carbon, hydrogen, and oxygen atoms. Their unique ring-shaped structure, with eight linear units extending from each crystal, has earned them the moniker “The Octopus.”
These versatile crystals go beyond iodine capture; the research team has also employed them to capture carbon dioxide, contributing to a cleaner and more sustainable world. Additionally, the molecular structure of “The Octopus” molecules bears similarities to materials used in lithium-ion batteries, hinting at potential applications in alternative energy sources.
Professor Ognjen Miljanic, leading the research team working with these crystals, expressed excitement about their vast potential and the prospect of exploring various practical applications. He envisions finding a partner to support further research and explore commercial aspects of this revolutionary technology.
While this breakthrough holds immense promise, additional research will focus on studying the kinetics and behaviour of the crystal structures to enhance their capabilities further. The study received funding from the National Science Foundation, underscoring the significance and potential impact of this groundbreaking research.